Hi Mr Spock,
Could you please explain what features might be missing from an apk version of the DJI Go4 app? I am using the .5 version (down-graded from the latest .7 app, as it gave me Gimbal and video issues) that I installed onto my Galaxy S5. I can't see any feature that may not be present as compared to the app store version. I keep auto-update off on my phone, so that I have total control over what gets updated, and I fly on airplane mode. I suppose I should really be using the .3 app version, as this was closest to the .400 FW if I'm correct.
Regards Smokey.